Spark Plug Gap

[jumpfroggy]

Most books I've read say to use the gap plug tool to close up the gap. Most of them have a little notch built in to use for this purpose. It's easy to picture but hard to describe how this works...

The "L" shaped electrode that sticks out of the spark plug is what you're adjusting. The gap tool grabs onto the vertical part (if you were to hold the sparkplug vertically) and adjust closer or further from the center electrode. This will move the horizontal part closer or further from the center electrode. I don't know why, the book seems to be firm that this is the correct way to do it. Anyone know why? Does everyone else just smash it from the top?

Let us know if the correct gap fixes it, I'm curious now too.

 

[JayRolla]

Actually I wanted this thread to die, but the car only missfires in the cold weather now. Its fine above 40*. In CO it can be 20* in the morning and 70* by noon and back to 20* by 9 at night. Its insane, and the car does not like it. I lowered the gap to .026 and no effect.

 

[eclipsegsx1736]

Have you tried your old parts one at a time? Start with the old plugs first, see if it goes away. Maybe you just got a bad plug? Also, how bad is this misfire? When I started running higher boost, I would get a very slight miss under boost especially when cold (although it doesn't get all that cold here), and I gapped my BPR7ES to .026 and haven't had the problem since.

 

[JayRolla]

No I havnt tried the old plugs, im going to get some new ones because I dropped a couple of the old ones. Actually since I lowered the gap it has not been cold for me to test it. I know I stated earlier I did but I remember its been warm the last few days. Maybe I did fix it, but I do get a very very slight hesitation at high rpm even when warm out. I need to do another log I may be have some knock or something.

 

[Defiant]

yea they told me 32 also... Do I have to smash them down a little to ungap them?

You should be using a wire plug gauge, not one of those discs-with-a-ramp. They include a "wrench" you use gently on the side of the electrode to bend it down.
Never, ever, ever tap the electrode against a hard surface like the top of the alternator housing like every last mechanic on the face of the earth always does. Because it's bad to. Somehow it's believed by guys who sell sparkplugs, but who have never actually touched one that had ever been fired, that this tapping will somehow cause the side electrode to fail and bring about The Apocalypse. And no, don't ask them how it's going to survive in a 4,000° F atmosphere while enduring explosive gasoline fumes fifty and more times a second if it's so candy-assed fragile, because they get all weird when you make a point that makes them look even more stupid than that godawful tie they're wearing.

 

[Defiant]

Of course, you could always take the coward's way out, and just use gapping pliers.
http://images.google.com/imgres?img...refox-a&rls=org.mozilla:en-US:official_s&sa=G

 

[ILLiCliPSE]

I just put in new spark plugs and i gapped them to .030. They were over .028 when they came out of the box and they were all basically on .030...so i just made every one equal and I have no problems.

 

[Rice Over Wheat]

All my BPR8ES that I've ever gotten from Discount Auto Parts has come gapped to .30 right out of the box. So I don't bother messing with them after I verify.

 

[Defiant]

Well, perhaps it'll sink-in if it comes straight from NGK:

http://www.ngksparkplugs.com/techinfo/spark_plugs/installation.asp?nav=31300&country=US


3. Gapping

Since the gap size has a direct affect on the spark plug's tip temperature
and on the voltage necessary to ionize (light) the air/fuel mixture, careful attention is required. While it is a popular misconception that plugs are pre-gapped from the factory, the fact remains that the gap must be adjusted for the vehicle that the spark plug is intended for. Those with modified engines must remember that a modified engine with higher compression or forced induction will typically require a smaller gap settings (to ensure ignitability
in these denser air/fuel mixtures). As a rule, the more power you are making, the smaller the gap you will need.

A spark plug's voltage requirement is directly proportionate to the gap size. The larger the gap, the more voltage is needed to bridge the gap. Most experienced tuners know that opening gaps up to present a larger spark to the air/fuel mixture maximizes burn efficiency. It is for this reason that most racers add high power ignition systems. The added power allows them to open the gap yet still provide a strong spark.

With this mind, many think the larger the gap the better. In fact, some aftermarket ignition systems boast that their systems can tolerate gaps that are extreme. Be wary of such claims. In most cases, the largest gap you can run may still be smaller than you think.

 

[Rice Over Wheat]

Reminds me of those splitfire commercials in the 1990s. +5 hp guaranteed!

 

[VxminhxL]

I had the same problem with my car. It was sputtering or bogging around 6000rpm. If you arent already, try using the single prong spark plugs they make a whole lot of difference and are cheaper too. Sometimes paying more isnt better. good luck